Effects of joint toxicity of mercury and another heavy metal on luminescent bacteria

The joint toxicity effects of heavy metals on luminescent bacteria Photobacterium phosphoreum T3 were investigated. The joint and integral toxicity of Mercury, Plumbum, Cadmium and Chromium were tested by oceanic luminous bacteria. The concentrations of each kind of heavy metal in mixture were determined by a statistical method called general regression circumrotate experimental design and the test results were analyzed using software such as SAS, MINTAB etc. Three function models were built which showed that the toxicity of each heavy metal on luminescent bacteria was usually in positive effect. The effects of toxicity on bacteria vary through concentration of heavy metals in mixtures. As for the three kinds of mixtures containing Mercury the binary toxicity of mixtures was different from each other. Generally, the binary toxicity of Mercury and Plumbum is synergism. The binary toxicity of Mercury and Cadmium is only addictive, and the binary toxicity of Mercury and Chromium is antagonism. From the view of single heavy metal effect, the toxicity effects of Mercury are outweighed over the other metal in mixture. The determination of joined toxicity of various kinds of mixture of pollutants using luminescent bacteria is a rapid, cheap and easy biological method which can be used widely in the assessment of farm product pollution and the detection of products safety in the future.